// Copyright 2020 Tokamak contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// FIXME: these should have standalone implementations
public extension View {
  @_spi(TokamakCore)
  func _onMount(perform action: (() -> ())? = nil) -> some View {
    modifier(_AppearanceActionModifier(appear: action))
  }

  @_spi(TokamakCore)
  func _onUpdate(perform action: (() -> ())? = nil) -> some View {
    modifier(_LifecycleActionModifier(update: action))
  }

  @_spi(TokamakCore)
  func _onUnmount(perform action: (() -> ())? = nil) -> some View {
    modifier(_AppearanceActionModifier(disappear: action))
  }
}

protocol LifecycleActionType {
  var update: (() -> ())? { get }
}

struct _LifecycleActionModifier: ViewModifier {
  var update: (() -> ())?

  typealias Body = Never
}

extension ModifiedContent: LifecycleActionType
  where Content: View, Modifier == _LifecycleActionModifier
{
  var update: (() -> ())? { modifier.update }
}
